Actual efforts to use Michel FOUCAULT's ideas about discourse for empirical research induce a linguistic bias which misses FOUCAULT's interests in power/knowledge. Against such tendencies, this article argues for a grounding of discourse theory and empirical discourse research in the sociology of knowledge, especially in the German-based Hermeneutische Wissenssoziologie, which follows the BERGER/LUCKMANN approach to knowledge. For the purposes of empirical discourse research on knowledge, the author first considers the interpretative dimension of research. Then, some conceptual tools for knowledge analysis are presented (interpretative scheme, classification, phenomenal structure, narrative structure). Third, drawing on grounded theory and sequential analysis, concrete work on texts is discussed. Finally, the article insists that discourse research should not be reduced to the analysis of spoken or written texts. Instead, different kinds of materiality—for example as dispositifs—have to be considered.